RCA 6SN7GT BLACK GLASS OLD STYLEYou are looking at a pair of RCA 1940's production 6SN7GT dark glass. The tubes are early version of RCA made with black coating inside the glass for shielding. They are not the GTA nor GTB version and this is one of the best 6SN7 variants. They are are sought after by audiophiles for its rich harmonics and sweet sounding. The tubes were tested very strong on my TV-7B/U tester with reading of 104 & 104 and 104 & 106, well above typical NOS tubes reading. The minimum good reading of the 6SN7 tube on this tester is 50 & 50. No Short, no Gas found on both tubes. I accept Paypal for payment. Shipping is $6 for US Postal Service Priority Mail® in USA. International winner will pay the actual cost of shipping. First Class Mail International is OK for selected countries. Please email to ask. Please check my other listing and feedbacks and . Thank you for reading.